The present invention relates to liquid pumps; more particular, the invention relates to an improved liquid pump construction for facilitating preventive maintenance and repairs to the pump, particularly at the job site.
Liquid pumps of the type relating to this invention are typically used in industrial applications, where the pump may be installed at a location where access is limited, or where it is important to perform preventive maintenance operations or repairs without physically removing the pump from the job site. It is always desirable to be able to perform preventive maintenance or repair operations in the shortest possible time, to provide minimum interruption to the industrial activity in which the pump is associated.
Liquid pumps of the general type disclosed herein are reciprocable pumps, comprising a piston reciprocable within a cylinder, with the piston connected to an external driving source via a piston or displacement rod. The cylinder typically has a lower intake valve and an upper discharge port, and the piston has a piston valve to selectively isolate the interior of the cylinder into two compartments. The lower portion of the cylinder is immersed into a liquid container, with the intake valve beneath the liquid level in the container. During the suction stroke the piston is raised within the cylinder, closing the piston valve and opening the intake valve, thereby drawing liquid into the cylinder below the piston and expelling liquid through the discharge port above the cylinder. During the pressure stroke the piston is forced downwardly within the cylinder, closing the intake valve and opening the piston valve, thereby forcing liquid in the lower portion of the cylinder beneath the piston to flow through the piston valve into the upper portion of the cylinder above the piston and outwardly through the discharge port.
The component parts of the pump which are subject to wear are readily discernable, and it is these parts which require preventive maintenance and repair from time to time. For example, the piston packings and glands, the cylinder, the piston valve and the intake valve are all subject to relatively high wear. The need for periodic preventive maintenance of these parts is predictable, and the need for occasional repair is expected. Therefore, it is desirable to design the pump so that access to these parts can be made quickly, and without requiring disassembly of substantial portions of the pump to achieve this access. It is a principal object of the present invention to provide a pump construction which permits quick and efficient access to these component parts, particularly without requiring removal and disassembly of the entire pump to accomplish preventive maintenance and repair operations, and without the requirement of removing the entire pump from its mounting or application.